1909609 has 4 divisors (see below), whose sum is σ = 2056516. Its totient is φ = 1762704.

The previous prime is 1909603. The next prime is 1909619. The reversal of 1909609 is 9069091.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9069091 = 379 ⋅23929.

It can be written as a sum of positive squares in 2 ways, for example, as 462400 + 1447209 = 680^2 + 1203^2 .

It is a cyclic number.

It is not a de Polignac number, because 1909609 - 2¹¹ = 1907561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1909603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 73434 + ... + 73459.

It is an arithmetic number, because the mean of its divisors is an integer number (514129).

2^1909609 is an apocalyptic number.

It is an amenable number.

1909609 is a deficient number, since it is larger than the sum of its proper divisors (146907).

1909609 is a wasteful number, since it uses less digits than its factorization.

1909609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 146906.

The product of its (nonzero) digits is 4374, while the sum is 34.

The square root of 1909609 is about 1381.8860300329. The cubic root of 1909609 is about 124.0646774971.

It can be divided in two parts, 190960 and 9, that added together give a square (190969 = 437²).

The spelling of 1909609 in words is "one million, nine hundred nine thousand, six hundred nine".